Skidding system for a catwalk

ABSTRACT

A skidding system is provided for laterally moving a catwalk. The system can include a plurality of legs placed about the perimeter of the catwalk. Each leg can extend and contract in length. The lower end of each leg can include a trolley member slidably coupled to a foot assembly. The catwalk can be moved laterally by extending the legs to raise the catwalk off of the ground, moving the trolley members within the foot assemblies and then contracting the legs to lower the catwalk to its new position.

FIELD OF THE INVENTION

The present invention is related to the field of skidding systems for catwalks, more particularly, skidding systems that move catwalks laterally with respect to drilling rig platforms.

BACKGROUND

Pipe launchers are used for presenting and receiving sections of pipe to and from drilling rig platforms. They are often referred to as “catwalks” as they include platforms that run along their length for service personnel to walk upon. As catwalks can weigh several tonnes, their initial placement may not be exact or ideal for presenting and receiving sections of pipe to and from the drilling rig platform.

It is, therefore, desirable to provide a skidding system for catwalks that permits movement of the catwalk to better position the catwalk with respect to a drilling rig platform.

SUMMARY OF THE INVENTION

A skidding system is provided for catwalks that permits side-to-side, fore and aft, diagonal or rotational movement of the catwalk to better position the catwalk relative to the drilling rig platform.

In one embodiment, the system includes a plurality of substantially vertical legs that are operatively attached to a catwalk about its perimeter. A vertical leg can be placed at or near each corner of a catwalk. For larger catwalks, additional vertical legs can be placed at one or more midpoints along the length of the catwalk. Each vertical leg can extend in length to raise the catwalk off of the ground, and can further contract in length to lower the catwalk to the ground.

In another embodiment, each vertical leg can include a trolley member operatively coupled to a lower end of the vertical leg. In a further embodiment, a foot assembly is slidably coupled to each trolley member whereby the trolley member can move substantially horizontal relative to the foot assembly. In operation, foot assemblies can be oriented in the same direction, typically but not necessarily, perpendicular to the length of the catwalk.

When the foot assemblies are perpendicular to the catwalk, the catwalk can be moved laterally or side-to-side. When the foot assemblies are parallel to the catwalk, the catwalk can be moved fore and aft. When the foot assemblies are placed at substantially the same angle relative to the catwalk, the catwalk can be moved diagonally. When each foot assembly is positioned substantially parallel or tangent to the perimeter of an imaginary circle centred on the approximate centre of the catwalk, the catwalk can be rotated or moved in a circular fashion about its centre.

To move the catwalk, the vertical legs are extended in length to contact the ground and raise the catwalk a sufficient distance off of the ground. In one embodiment, the vertical legs can be extended through the use of hydraulic cylinders. Once lifted off of the ground, the catwalks can be moved by moving each trolley member horizontally in its respective foot assembly. In another embodiment, hydraulic cylinders can be used to move the trolley members within the foot assemblies. Once the catwalk has moved, the vertical legs can be contracted in length to lower the catwalk back to the ground.

A catwalk can be provided with the skidding system described herein. In other embodiments, the skidding system described herein can be provided separately for use for catwalks. The skidding systems described herein can also be provided as a kit to retrofit existing catwalks.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view depicting a vertical leg assembly for a catwalk skidding system.

FIG. 2 is a perspective view depicting an alternate embodiment of the vertical leg assembly of FIG. 1.

FIG. 3 is a side elevational view depicting the support leg member of the vertical leg assembly of FIG. 2.

FIG. 4 is a top plan view depicting the support leg member of FIG. 3.

FIG. 5 is a perspective view depicting the vertical hydraulic cylinder of the vertical leg assembly of FIG. 2.

FIG. 6 is a front elevational view depicting the hydraulic cylinder of FIG. 5.

FIG. 7 is a side elevational view depicting the hydraulic cylinder of FIG. 5.

FIG. 8 is a perspective view depicting the foot assembly of the vertical leg assembly of FIG. 2.

FIG. 9 is a perspective view depicting the trolley member of the foot assembly of FIG. 8.

FIG. 10 is a perspective view depicting the foot coupler of the trolley member of FIG. 9.

FIG. 11 is a perspective view depicting a catwalk prior to being moved laterally.

FIG. 12 is a perspective view depicting the catwalk of FIG. 11 being moved laterally.

FIG. 13 is a perspective view depicting the catwalk of FIG. 11 after being moved laterally.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Referring to FIG. 1, one embodiment of a skidding system for a catwalk is shown. Skidding system 10 can include support leg assembly 11 that can comprise frame rails 12 a and 12 b, vertical frame member 13, diagonal frame member 16 and vertical leg 19 that can comprise fixed leg member 18 and movable leg member 20 slidably coupled thereto. In the illustrated embodiment, fixed leg member 18 can form part of support leg assembly 11. Support leg assembly 11 can be attached to a catwalk (not shown) by connecting frame ends 14 a and 14 b to the catwalk frame with pins 15. It should be obvious to those skilled in the art that skidding system 10 can be operatively attached to a catwalk frame in any number of suitable ways that include the illustrated embodiment, other methods of releasable attachment through the use of pins or bolts or by permanently attaching support leg assembly to the catwalk frame, either by welding or any other suitable forms of permanent attachment.

Referring to FIGS. 1 and 2, movable leg member 20 can be nested within fixed leg member 18 whereby movable leg member 20 can move in and out or “telescope” with respect to fixed leg member 18 to extend or contract the length of leg 19. In the illustrated embodiment, hydraulic cylinder 22 can be connected to both fixed leg member 18 and to movable leg member 20, and the lower end of removable leg member 20 can be operatively coupled to trolley member 26 at swivel foot coupler 48. In another embodiment, trolley member 26 can be slidably coupled to foot assembly 24. In the illustrated embodiment, foot assembly 24 can include foot frame 30 that includes side plates 46, end plates 28 and 29, angle plates 47, trolley tracks 44, cleats 40 and handle 58. Foot assembly 24 can further comprise cylinder 32 that is connected to both foot frame 30 and trolley member 26 to provide the means to move trolley member 26 within foot assembly 24. In the embodiment shown in FIG. 2, frame ends 14 a and 14 b can be inserted into openings 9 a and 9 b of catwalk frame 42 and be secured by pins 15 passing therethrough.

Referring to FIGS. 3 and 4, an embodiment of support leg assembly 11 is shown. As illustrated, both fixed and movable leg members can be square in cross-sectional area whereby movable leg member 20 is nested within fixed leg member 18. The relative dimensions of the leg members are selected whereby movable leg member 20 is fitted within fixed leg member 18 with minimal clearance so as to provide a structurally stable leg yet permit movable leg member 20 to move within fixed leg member 18 with relative ease. The overall dimensions and sidewall thickness of the leg members can easily be determined by a person skilled in the art for any particular catwalk having regard to the overall weight of the catwalk and the number of skidding systems 10 being used.

It should be obvious to a person skilled in the art that other embodiments of the leg members can include fixed member 18 being nested within movable leg member 20. It should also be obvious that the cross-sectional shape of the leg members can be triangular, rectangular, circular, elliptical, polygonal, kidney-shaped or combinations thereof or any other suitable cross-sectional shape that allows movable leg member 20 to move relative to fixed leg member 18 and maintain structural stability. Referring to the illustrated embodiment shown in FIG. 3, movable leg member 20 can include ball 50 disposed at its lower end. Ball 50 can couple to swivel foot coupler 48 located on top of trolley member 26 as shown in FIG. 2.

Referring to the illustrated embodiment shown in FIGS. 4 to 7, cylinder 22 can be mounted on the exterior of the leg members. In this illustrated embodiment, cylinder 22 can be hydraulically activated with hydraulic fluid supply and return hoses (not shown) attached to connector fittings 23 a and 23 b and controlled by hydraulic control systems as well known to those skilled in the art. As shown, one end of cylinder 22 can be coupled to bracket 52 with pin 54. Bracket 52 can be attached to fix leg member 18 via welding or other suitable attachment means, or can be an integral unit to fixed leg member 18.

The other end of cylinder 22 is attached to bracket 56 with pin 54. Bracket 56 is attached to movable leg member 20. Thus, as cylinder 22 is activated to extend in length, movable leg member 20 is moved downward relative to fixed leg member 18. When cylinder 22 is activated to contract in length, movable leg member 20 is retracted into fixed leg member 18. While cylinder 22 has been shown mounted on the exterior of the leg members, it should be obvious to a person skilled in the art that other embodiments can include cylinder 22 being disposed within the leg members. It yet further embodiments, movable leg member 20 and cylinder 22 can be one and the same element where the stationary portion of cylinder 22 is disposed within fixed leg member 18 and the cylinder or ram portion of cylinder 22 can be movable leg member 20.

It should also be obvious to a person skilled in the art that cylinder 22 being a hydraulic ram cylinder is a choice made as a matter of convenience and not of necessity. Pneumatically operated ram cylinders or air springs can substitute for cylinder 22 to provide means to extend the length of leg 19 to lift a catwalk. In yet other embodiments, cylinder 22 can be substituted with screw jack-type devices that can extend and contract in length to provide the same functionality of cylinder 22.

Referring to FIG. 8, an embodiment of foot assembly 24 is shown. Broadly speaking, foot assembly 24 can comprise trolley member 26 slidably coupled to foot frame 30. In this illustrated embodiment, frame 30 can comprise side plates 46, end plates 28 and 29 and bottom plate 31. Angle plates 47 can be attached to side plates 46 to keep trolley member contained within foot frame 30. Disposed on top of bottom plate 31 are trolley tracks 44. Two substantially parallel tracks 44 can be provided although only one is visible in FIG. 8 as shown. Tracks 44 can provide a path for trolley rollers 36 on trolley member 26 to roll upon. Cleats 40 can be added to the bottom of plate 31 to prevent foot frame from slipping when in contact with the ground.

In operation, trolley member 26 can move along trolley tracks 44 as cylinder 32 is extended or contracted in length. One end of cylinder 32 can be attached to anchor block 43 with pin 45. The other end of cylinder 32 can be attached to trolley member 26 (not shown). Similar to cylinder 22, cylinder 32 can be a hydraulic cylinder with hydraulic fluid supply and return hoses (not shown) attached to connector fittings 33 a and 33 b and controlled by hydraulic control systems as well known to those skilled in the art. In other embodiments, cylinder 32 can be substituted with a pneumatic ram cylinder, an air spring or a screw jack-device of device or any other suitable type of device as known to those skilled in the art. Handle 58 disposed on end plate 29 provides means for service personnel to manually position foot assembly 24 with respect to the catwalk when lifted off of the ground.

Referring to FIG. 9, an embodiment of trolley member 26 is shown. In this embodiment, trolley member 26 can be comprised of top plate 60 and side plate 62 extending downwardly from top plate 60 along its edges. Trolley rollers 36 can be rotatably attached to side plate 62 by having a threaded member extending through holes in side plate 62 and secured by a net through a hole in side plate 62 and secured by nut 68. Trolley rollers 36 can be configured to roll on trolley tracks 44 as shown in FIG. 8. In the illustrated embodiment in FIG. 8, trolley tracks 44 are V-shaped in profile with trolley rollers 36 having a similar profile. This profile is chosen as a matter of convenience and not necessity. It should be obvious to a person skilled in the art that other profiles can be used that allow trolley rollers 36 to track on trolley tracks 44.

Referring to FIGS. 9 and 10, an embodiment of swivel foot coupler 48 is shown. In this embodiment, coupler 48 comprises both socket 66 and swivel foot cover 64. Coupler 48 can be attached to top plate 60 with bolt 74 passing through hole 76 into corresponding threaded holes in top plate 60 (not shown). As illustrated, ball socket 66 is spherical to receive ball 50 as shown in FIGS. 4 to 7. Ball 50 is coupled to coupler 48 by inserting ball 50 into ball socket 66 and then placing swivel foot cover 64 over ball 50 and threading bolts 71 through swivel foot cover 64 into corresponding threaded holes in coupler 48 (not shown).

The use of ball 50 and coupler 48 can allow the lower end of movable leg member 20 to be operatively coupled to foot assembly 24 and still allow foot assembly 24 to rotate in more than one direction relative to movable leg member 20. In so doing, foot assembly 24 can rotate as required when it is in contact with the ground if the ground is not smooth or level. Coupler 48 can also allow each foot assembly 24 to be moved to any position relative to a catwalk.

As an example, all foot assemblies 24 can be placed perpendicular to the catwalk so that the catwalk can be moved laterally or side-to-side. As another example, all foot assemblies 24 can be placed parallel to the catwalk so that the catwalk can be moved fore and aft. In a further example, all foot assemblies 24 can be placed at substantially the same angle relative to the catwalk so that the catwalk can be moved diagonally. In yet a further example, each foot assembly 24 can be placed substantially parallel or tangent to the perimeter of an imaginary circle centred on the approximate centre of the catwalk so that the catwalk can be rotated or moved in a circular fashion about its centre.

It should be obvious to those skilled in the art that the choice of a ball and socket to operatively couple movable leg member 20 to foot assembly 24 is one of convenience and not necessity. Other embodiments can include the use of universal joints, constant velocity joints or any other suitable coupling joints as well known to persons skilled in the art.

Referring to FIGS. 1 1 to 13, a catwalk is shown being moved using the skidding system described herein. In FIG. 11, catwalk 80 is resting on the ground waiting to be moved laterally. In this example, a skidding system 10 is placed near each corner of catwalk 80. More skidding systems 10 can be added if required. Foot assemblies 24 are lowered on each skidding system 10 until they contact the ground. In FIG. 12, movable leg member 20 in each skidding system 10 is lowered until catwalk 80 is raised distance 82 off of the ground. Each trolley member 26 in each skidding system 10 is then moved laterally in its respective foot assembly 24 whereby catwalk 80 is moved laterally horizontal distance 84. In FIG. 13, foot assemblies 24 are raised to lower catwalk 80 to its new position. Once catwalk 80 is on the ground, foot assemblies 24 can continue to be raised to fully nest movable leg members 20 in fixed leg members 18.

Although a few illustrative embodiments have been shown and described, those skilled in the art will appreciate that various changes and modifications might be made without departing from the scope of the invention. The terms and expressions used in the preceding specification have been used herein as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims that follow. 

1. A skidding system for a catwalk having a plurality of support leg assemblies extending therefrom, the system comprising: a) a substantially vertical leg configured for operative attachment to each of the support leg assemblies, the vertical leg capable of extending and contracting in length; b) means for extending and contracting the vertical leg; c) a trolley member operatively coupled to a lower end of the vertical leg; d) a foot assembly slidably coupled to the trolley member whereby the trolley member is capable of moving substantially horizontal relative to the foot assembly; and e) means for moving the trolley member relative to the foot assembly.
 2. The system as set forth in claim 1 wherein the vertical leg further comprises a fixed leg member and a movable leg member slidably coupled thereto whereby the movable leg member is capable of telescoping in and out relative to the fixed leg member.
 3. The system as set forth in claim 1 wherein the means for extend and contracting the vertical leg comprises at least one of the group consisting of a hydraulic ram cylinder, a pneumatic ram cylinder, an air spring and a screw jack.
 4. The system as set forth in claim 1 wherein the trolley member further comprises a plurality of trolley rollers.
 5. The system as set forth in claim 4 wherein the foot assembly further comprises tracks for the trolley rollers.
 6. The system as set forth in claim 1 wherein the means for moving the trolley member further comprises at least one of the group consisting of a hydraulic ram cylinder, a pneumatic ram cylinder, an air spring and a screw jack.
 7. A kit for a catwalk, comprising: a) a plurality of support leg assemblies for attaching to the catwalk; b) a plurality of substantially vertical legs configured for operative attachment to the support leg assemblies, the vertical legs capable of extending and contracting in length; c) means for extending and contracting each vertical leg; d) a trolley member operatively coupled to a lower end of each vertical leg; e) a foot assembly slidably coupled to each trolley member whereby each trolley member is capable of moving substantially horizontal relative to the foot assembly; and f) means for moving the trolley member relative to the foot assembly.
 8. The kit as set forth in claim 7 wherein the vertical leg further comprises a fixed leg member and a movable leg member slidably coupled thereto whereby the movable leg member is capable of telescoping in and out relative to the fixed leg member.
 9. The kit as set forth in claim 7 wherein the means for extend and contracting the vertical leg comprises at least one of the group consisting of a hydraulic ram cylinder, a pneumatic ram cylinder, an air spring and a screw jack.
 10. The kit as set forth in claim 7 wherein the trolley member further comprises a plurality of trolley rollers.
 11. The kit as set forth in claim 10 wherein the foot assembly further comprises tracks for the trolley rollers.
 12. The kit as set forth in claim 7 wherein the means for moving the trolley member further comprises at least one of the group consisting of a hydraulic ram cylinder, a pneumatic ram cylinder, an air spring and a screw jack.
 13. A catwalk having a plurality of support leg assemblies extending therefrom, the improvement comprising: a) a substantially vertical leg operatively attached to each support leg assembly, the vertical legs capable of extending and contracting in length; b) means for extending and contracting each vertical leg; c) a trolley member operatively coupled to a lower end of each vertical leg; d) a foot assembly slidably coupled to each trolley member whereby each trolley member is capable of moving substantially horizontal relative to the foot assembly; and e) means for moving each trolley member relative to the foot assembly.
 14. The catwalk as set forth in claim 13 wherein the vertical leg further comprises a fixed leg member and a movable leg member slidably coupled thereto whereby the movable leg member is capable of telescoping in and out relative to the fixed leg member.
 15. The catwalk as set forth in claim 13 wherein the means for extend and contracting the vertical leg comprises at least one of the group consisting of a hydraulic ram cylinder, a pneumatic ram cylinder, an air spring and a screw jack.
 16. The catwalk as set forth in claim 13 wherein the trolley member further comprises a plurality of trolley rollers.
 17. The catwalk as set forth in claim 16 wherein the foot assembly further comprises tracks for the trolley rollers.
 18. The catwalk as set forth in claim 13 wherein the means for moving the trolley member further comprises at least one of the group consisting of a hydraulic ram cylinder, a pneumatic ram cylinder, an air spring and a screw jack.
 19. A method for moving a catwalk having a plurality of substantially vertical legs operatively attached thereon, the vertical legs capable of extending and contracting in length, each vertical leg having a trolley member operatively coupled to a lower end thereof, each trolley member slidably coupled to a foot assembly whereby each trolley member is capable of moving substantially horizontal relative to the foot assembly, the method comprising the steps of: a) extending the length of each vertical leg whereby the foot assemblies are contacting the ground and the catwalk is raised off of the ground; b) moving each trolley member relative to the foot assemblies whereby the catwalk moves from its former position; and c) contracting the length of the vertical legs whereby the catwalk is lowered onto the ground. 